Valuable and/or fragile objects often require storage or transportation in protective cases or containers. Typically, cases or containers which accommodate these objects are designed to be sturdy and strong. Although many different styles of containers exist, three primary designs are as follows, wherein the description is with respect to the figures described further below.
The first case style makes use a single base 1 and a single lid 2 is shown in FIG. 1A. An interior frame system (not shown) is typically located along the closure interface 10, or valance 10, between the lid 2 and base 1 of the case/container. This interior frame system is used to support the container's structural integrity, as well as generate and maintain alignment between the lid 2 and base 1. It must also resist lateral shearing forces at the lid—base interface, prevent dust and dirt from entering the closed case, and, when required, act as an impermeable seal. The lid may be hinged at 9 as shown in FIG. 1B.
The second case style, as shown in FIGS. 2A, 2B, comprises multiple base shells 4 each having an open top and bottom and two lids 2 which respectively enclose the ends of the assembled shells 4. The base shell 4 and lids 2 have similar lateral profiles; however, the depth of the base shells 4 and each lid 2 may differ. An interior frame system (not shown) is located along the closure interface 10, or valance 10, between each base shell 4 and at each lid 2 of the case. This interior frame system functions as in the first case, described above.
In order for containers, such as those described above, to maintain their shape and structural integrity, it is highly desirable that, at the valance 10 (e.g. at a lid-base or base shell-base shell boundary), the rigidity and alignment of the sub-frames carrying mating valance surfaces at the valance interface 10 be properly maintained. Any lateral movement produced at these boundaries will compromise the integrity of the container and potentially endanger the contents within.
Rectangular cases and containers use frame systems to increase rigidity at the valance and prevent unwarranted lateral movement between lid—base and base—base boundaries. The valance frame system typically consists of two continuous, complementary frame subassemblies 5 and 6, disposed around the perimeter of the opposing open faces of each adjacent container segment, cf. FIG. 3. These valance frame subassemblies must circumscribe the profile of the case in order to provide a complete seal.
In order for correct alignment to be attained and maintained at a valance interface, each corresponding pair of frame subassemblies should preferably have complementary profiles. That is to say, the valance interface of each pair of frame subassemblies must mate, preferably intimately.
Common complementary subassembly interface profiles may include the following styles:
Tongue and Groove:                (FIG. 4A) A. a male subassembly possessing a single protruding ridge profile and a female subassembly possessing a complementary, recessed groove profile.        (FIG. 4B) B. a male subassembly possessing a plurality of protruding ridge profiles and a female subassembly possessing a plurality of complementary recessed groove profiles.        
Hybrid:                (FIG. 5A) A. a male and female subassembly, each possessing complementary interface profiles, consisting of a single protruding ridge and a single recessed groove.        (FIG. 5B) B. male and female subassembly, each possessing complementary profiles, consisting of a plurality of protruding ridge and a plurality of recessed grooves.        
Rectangular cases and containers typically use metallic valance frame systems. The most common choice of metal is aluminum, as complex profiles can be readily extruded from this material in continuous lengths. Plastics may also be used as they are also readily extruded into complex profiles of continuous lengths.
The existing valance frame system used in conjunction with continuous valance frames in a container having tight radius corners often lacks substantial flexural strength and lateral shear resistance because the cross-sectional profile of such frames must be thin and simple enough to facilitate bending of the valance frame sub-section around the radius of the corner. The gap or a butt joint formed between the two ends of the bent frame member is also a point of flexural weakness (see item 17 in FIG. 3). Further, eliminating or minimizing the gap distance is difficult to achieve on a consistent, repeatable basis.
When constructing frame assemblies for various uses, it is known in the art to replace a corner of the frame with a unitary corner piece. For example, U.S. Pat. No. 4,045,104 describes “[a] cabinet structure [having] a plurality of tubular frame members having holes in the interior side walls thereof near the ends of the members, and a plurality or corner members for joining the frame members together . . . The corner members are fitted in the frame members by pivoting the legs thereof into the ends of the frame members so that the nipples are received into corresponding holes in the side walls of the frame members.”
U.S. Pat. No. 4,095,719 describes a typical sort of casing hardware in which the valance interface consists of a male and female joining edge, the female joining edge being provided with a rubber gasket to yield a stronger seal. There is no teaching, however, of a corner piece in this patent.
U.S. Pat. Nos. 4,691,970 and 3,815,966 both describe cabinets that use similar corner piece frame structure. Both describe cabinets in which all panel members are joined to an intermediary frame structure.
U.S. Pat. No. 3,784,043 describes a framing rail system for a collapsible structure. However, its corners are hermaphroditic such as those used in geodesic domes. As such the invention cannot be used for a container-type object that requires a means of opening and closing the container easily in order to seal the volume inside the container.
There exist many different references which make use of similar corner pieces in completing a frame assembly, including:    U.S. Pat. No. 5,820,289 patented Oct. 13, 1998 by Schroff GmbH    U.S. Pat. No. 3,272,582 patented Sep. 13, 1966 by E. V. Anderson et al    U.S. Pat. No. 5,066,161 patented Nov. 19, 1991 by R. C. Pinney    U.S. Pat. No. 6,561,603 patented May 13, 2003 by Knuerr-Mechanik fuer die Electronik Aktiengesellschaft    U.S. Pat. No. 5,020,866 patented Jun. 4, 1991 by Gichner Systems Group, Inc.    U.S. Pat. No. 6,223,917 patented May 1, 2001 by Octanorm-Vertriebs-GmbH fuer Bauelemente    U.S. Pat. No. 5,983,420 patented Nov. 16, 1999 by M. L. Tilley
The above references described frames for containers without focusing on the presence of a valance interface.
Oftentimes, due to the nature of the cargo, it is essential for the container or receptacle used for the transportation or storage of an object or objects to be substantially airtight and/or watertight. The following references offer examples of airtight or watertight containers:    U.S. Pat. No. 3,885,701 patented May 27, 1975 by Environment Container Systems, Inc.    U.S. Pat. No. 6,929,125 patented Aug. 16, 2005 by Foam Technologies, Inc.    U.S. Pat. No. 4,905,857 patented Mar. 6, 1990 by L. M. Her et al
For the most part, these patents address frame systems which run along three axes to provide a complete mechanical frame onto which sidewalls may be installed. Corner pieces in such systems extend outward on three axes (X, Y, and Z) so they may connect with three independent longitudinal frame members. The present invention preferably addresses a 2-axis or planar frame arrangement which serves to provide the base-base and lid-base valances subassemblies.
It would therefore be advantageous to provide corner pieces for a valance interface that are distinguished from the prior art by being simple in construction while having substantial strength and rigidity, and being resistant to lateral shearing forces and misalignment. Such a valance interface is suitable for use around the closing edges of lidded containers but also has applications in any situation where a valance interface is formed, e.g. around the perimeter of a doorframe.
The invention in its general form will first be described, and then its implementation in terms of specific embodiments will be detailed with reference to the drawings following hereafter. These embodiments are intended to demonstrate the principle of the invention, and the manner of its implementation. The invention in its broadest and more specific forms will then be further described, and defined, in each of the individual claims which conclude this Specification.